Dr John Briffa: Bed and bored

In a recent column I explored how keeping blood-sugar levels stable in the small hours helps to promote restful sleep and reduces the risk of unwanted awakenings. This week, I was reminded of another foodrelated influence on slumber by a study which found that many of those with sleep issues suffer from stomach-acid reflux at night. For many, rising acid at night will cause obvious symptoms. However, this new research has found that reflux can disturb sleep without any obvious symptoms. It seems that when stomach contents rise at night, our chances of getting a decent night's sleep can go belly up.

While acid reflux can be effectively suppressed with medication, my experience is that it almost always responds to a natural approach. The risk of night-time regurgitation is reduced by taking steps to ensure that the stomach has made a good job of digesting supper before bed. Ensuring supper is eaten at least three or four hours prior to getting our head down helps, though busy lives can make this difficult. However, one way of mitigating against the effects of a late supper is to limit the size of this meal. One simple tactic that can help is to reduce our appetite in the evening by having a snack (eg some fruit and nuts) in the late afternoon.

Not being too ravenous at suppertime also reduces the risk that we will bolt our food and eschew thorough chewing - proper mastication aids digestion, principally by breaking food up into smaller particles that are more easily penetrated by stomach acid and other digestive juices. Another simple mealtime tip that ensures more efficient digestion is to drink as little as possible during the meal and for a few hours afterwards: significant quantities of fluid in the upper digestive tract dilutes stomach acid and enzymes in the small intestine, which serves only to impair our digestive capacity.

One other dietary tactic that may help combat nocturnal reflux is to keep protein-rich foods (such as meat, fish and egg) away from starches (such as potatoes, rice and pasta) at suppertime. In theory, this makes digestion easier, and increases the chances that the stomach will be relatively empty by bedtime. Meals which comply with this way of eating include meat or fish combined with vegetables other than the potato, or a pasta or rice-based dish accompanied only by vegetables. This approach is usually highly effective in controlling symptoms such as indigestion and heartburn. Taking steps to enhance digestion helps ensure that acid reflux isn't anything to lose sleep over.

Dear John

As a life-long vegetarian, I was surprised to find you recommending omega-3-enriched eggs for vegetarian children in your column of 30 October. These contain fish oils, principally from tuna, and are not suitable for vegetarians who reject all animal slaughter. Roger Grimshaw, Haslemere

Omega-3-enriched eggs come from hens fed a diet rich in omega-3 fats. Some are fed fish-derived feed, but not all. For example, the market-leading Columbus eggs come from hens fed a vegetarian diet rich in flaxseed (linseed), which contains an omega-3 fat, alpha-linolenic acid. At least some of this converts into docosahexaenoic acid (DHA), which is also found in fish oil and is linked to healthy brain formation. You state that vegetarians reject all animal slaughter. While I am very respectful of those who object to the killing of animals for food, not all vegetarians avoid animal flesh because of moral convictions. Some dislike the taste and/or texture. Eggs from hens fed fish-derived omega-3 fats may be acceptable to them, and offer a relatively cheap and practical way of boosting omega 3 intake.

· If you have any issues you would like Dr Briffa to address in his column, please email him on john.briffa@observer.co.uk. Please note that Dr Briffa cannot enter into any correspondence. You can also visit www.drbriffa.com. Before following any recommendations in this column, you should consult your own medical adviser about any medical problems or special health conditions

Nutrition news

Cervical cancer is preceded by abnormalities in the cells of the cervix known as 'cervical intra-epithelial neoplasia' (CIN). Previous studies have suggested that the nutrient folate may have some capacity to reduce the risk of CIN. One effect of this vitamin is to help ensure normal division of the body's cells - something which would be expected to reduce the risk that cells will undergo abnormal or cancerous change. The relationship between folate and CIN was assessed in a study published recently in the journal Nutrition Research.

The study examined more than 200 Thai women, about half of whom were affected by CIN. The study found that women with CIN had significantly lower levels of folate in their bodies compared to those without this condition. Low folate levels were associated with about a sixfold increase in risk of CIN. This study provides further support to the notion that high intakes of folate may help to protect against CIN and cervical cancer. Good sources of folate include green beans, lentils and green leafy vegetables. In addition to including plenty of these foods in the diet, it might also help to supplement with folic acid at a dose of about 400 mcg per day.